The curve below is given by the parametric equations

The points $P$ and $Q$ lie on the curve and additionally satisfy $y=|x|$.

The tangents to the curve at $P$ and $Q$ are drawn, and the shaded area is enclosed between the curve and the tangents.

Find the exact value of the shaded area.

The area can be given in the form $\frac{a}{b}$.

Give the value of $ab$.